My goodness! I could have written your post word for word 5 months ago! :lol:
Prior to starting solids at 6.5 months, I was doubling up feeds every 2 hours and he was taking a good 60 oz a day (could take 12 oz from a bottle in ONE sitting!!). He still had that one milk feed during the night and often woke at other times (though I didn't feed him). I was becoming harried and haggard!!
After one week of having three solid meals at day, he started sleeping through (added one meal a week until we were up to three)! It was the easiest thing ever! I could hardly believe it. After we started the three meals, I noticed his night feed dropped to half the time almost immediately. That's how I got the clue. On normal nights, if he wakes before a certain time, I won't feed him and put him back to sleep another way (then feed him the next timehe wakes). So I got the courage one night to just put him back to sleep without feeding. He didn't fight me. He woke an hour later and I did it again. Again, he went back to sleep with no issue and slept until morning! The next night, he completely slept through. We went for a week of him waking or sleeping through every other night, but I still didn't feed him. After that week, he's been sleeping through since, shortly after he turned 7 months old.
One trick I've learned since, once you're up to three meals, give cereal (or later, protien) during dinner. It seems to last longer through the night in their tummies than veggies or fruit.
Does your DD ever wake other times and you don't feed her? How do you soothe her back to sleep then? For my DS, he has a luvie and sucks his thumb. It was just a matter of finding his luvie in the crib and resettling him in his favorite position as fast as possible (before he woke too much).